Catheter apparatus with means for subcutaneous delivery of anesthetic agent or other fluid medicament

ABSTRACT

A novel catheter apparatus for use in delivering an anesthetic agent or other fluid medicament to the portion of subcutaneous tissue through which a catheter device has been inserted into a patient, thereby allowing the catheter device to be retracted without causing pain or discomfort to the patient. The catheter device has an indwelling cannula adapted for insertion through subcutaneous tissue into a patient&#39;s body. A helical sheath is formed from an elongate band that is wrapped around the cannula in a helical fashion so as to be capable of being positioned within the subcutaneous tissue once the cannula has been inserted into the body. The helical sheath has formed therein a lumen into which the anesthetic agent or other fluid medicament can be delivered via a hub that is connected to the proximal end of the helical sheath. The helical sheath has formed therein a plurality of delivery holes that form a fluid communication path with the lumen. The delivery holes permit the anesthetic agent or fluid medicament to be delivered to the surrounding subcutaneous tissue.

RELATED APPLICATION INFORMATION

This application is a continuation-in-part of U.S. application Ser. No.08/198,625, filed on Feb. 18, 1994 now U.S. Pat. No. 5,405,334, which isincorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to a catheter apparatus with a means forsubcutaneous delivery of anesthetic agents or other fluid medicaments,and more particularly to catheter apparatus having subcutaneous infusionports that provide for the administration of a local anesthesia or othermedicaments to an area of subcutaneous tissue through which a cannulahas been inserted.

2. The Present State of the Art

Catheter devices are widely used for a variety of medical applications.Generally, a catheter is a hollow, tubular cannula that is capable ofbeing inserted into canals, vessels, passageways, or other body cavitiesso as to permit injection or withdrawal of fluids, or to keep a passageopen. Other catheter devices are used for controlling, directing andplacing medical devices, such as intubation tubes or dilation catheters,into a body cavity, such as the trachea, a blood vessel, or the heart.These types of insertion catheters are commonly referred to asintubators, insertion sheaths, and/or dilators. Given that catheters areused for such a wide variety of applications, catheters are implementedin a variety of designs, shapes and sizes. However, when used, almostall catheters share the universal characteristic of having to be passedthrough the skin and subcutaneous tissue of the patient so as to beinserted into the proper body cavity.

Depending on the medical procedure, the catheter is very often left inthe body cavity over a relatively long period of time. As such, the skinand subcutaneous tissue through which the catheter device is insertedoften becomes very swollen and tender, and thus extremely sensitive.Consequently, when the catheter is eventually retracted from thepatient, the patient will often experience great discomfort. Thisdiscomfort may agitate the patient and thereby hinder the ability ofmedical personnel to effectively retract the catheter and/or treat thepatient.

For example, in a percutaneous transluminal coronary angioplasty (PTCA)procedure, a patient is administered a local anesthesia and anintravascular sheath introducer (a type of catheter device) is insertedthrough the patient's skin in the groin area and into the femoralartery. In so doing, the sheath introducer necessarily passes throughthe area of subcutaneous tissue that lies between the skin and thefemoral artery. Once inserted, the sheath introducer catheter provides ameans for introducing the dilation catheter for performing the PTCAprocedure.

Following the PTCA procedure, the sheath introducer is usually leftwithin the femoral artery for a period ranging between four totwenty-four hours. Typically, the sheath is left in place because bloodthinning drugs, such as Heparin, are administered to the patient. Theeffects of such drugs must wear off before the sheath can be removed inorder to avoid hemorrhaging problems. Similarly, the device may be leftin the patient as a precaution, in case quick access to the femoralartery is needed due to subsequent complications, such as an abruptclosure of the artery. In any event, by the time the sheath isretracted, the patient's skin and subcutaneous tissue through which thecatheter is inserted is typically very swollen, bruised and tender.Also, by this time, the numbing effects of the earlier administeredlocal anesthesia have completely worn off. Consequently, as the sheathis retracted from the femoral artery, the subcutaneous tissue and theoverlying skin, the patient can experience considerable pain.

Pain experienced during sheath removal is known to occasionally causevasovagal syncope type reactions, which can potentially result in avariety of undesirable patient responses--including a drop in bloodpressure and heart rate. This can be hazardous when it occurs so soonafter the PTCA procedure, and may thus require treatment withintravenous Atropine, or other drugs. Pain may also cause the patient tobecome agitated, which makes it difficult for medical personnel toproperly administer arterial compression. This can lead to a hematomaformation within the subcutaneous tissue adjacent to the catheter.

Although medical personnel can administer a local anesthesia to thearea, this must be done with a hypodermic needle, which usually causesas much discomfort or pain as the actual retraction of the catheterdevice. Thus, there is not a medical device available which adequatelyrelieves a patient's discomfort during catheter retraction, and there isa need to be able to administer a local anesthesia to the subcutaneoustissue surrounding a catheter device prior to the retraction of thedevice, in a relatively painless and easy manner.

BRIEF SUMMARY AND OBJECTS OF THE INVENTION

The apparatus of the present invention has been developed in response tothe present state of the art, and in particular, in response to theproblems involved with the pain and discomfort that is experienced by apatient when a catheter device is removed. Thus, it is an overall objectof the present invention to provide an apparatus which provides for theability to painlessly administer local anesthesia or other medicamentsto an area of subcutaneous tissue through which a catheter device hasbeen inserted.

A further object of the present invention is to provide an apparatusthat permits subcutaneous delivery of such medicaments but which alsoprevents bodily fluids from entering the apparatus while it is insertedand remains within the patient's body.

Yet another important object of the present invention is to provide ananesthetizing catheter sheath apparatus that can be manufactured eitheras an integral part of a catheter device, or as an apparatus that can bedetachably mounted to a catheter device.

Additional objects and advantages of the invention will be set forth inthe description which follows, and in part will be obvious from thedescription, or may be learned by the practice of the invention. Theobjects and advantages of the invention may be realized and obtained bymeans of the instruments and combinations particularly pointed out inthe appended claims.

Briefly summarized, the foregoing and other objects are achieved with acatheter apparatus that is inserted into a patient's body throughsubcutaneous tissue. In one presently preferred embodiment, a sheathfits over the catheter and is designed for insertion together with thecatheter through the subcutaneous tissue. Once the catheter device isinserted into the patient's body, the outer surface of the catheterdevice necessarily passes through the patient's skin and a portion ofunderlying, subcutaneous tissue. The sheath which is disposed on theouter surface of the catheter device is also thus inserted through thesubcutaneous tissue. Prior to retracting the catheter device, medicalpersonnel can administer an anesthetic agent by infusing it into thesurrounding subcutaneous tissue from the anesthetizing sheath. In thisway, the subcutaneous tissue will be numbed, and the patient willexperience no pain while the catheter device is retracted. In additionto anesthetic agents, the sheath can also be used to deliver a widevariety of other types of fluid medicaments to the subcutaneous tissue.For instance, the sheath may be used to deliver topical antibacterialagents to the tissue.

In one presently preferred embodiment of the present invention, theanesthetizing sheath apparatus can be permanently mounted to thecatheter device, and is thus manufactured as an integral part of thecatheter device.

In another presently preferred embodiment of the present invention, theanesthetizing sheath can be detachably mountable to the outer surface ofthe catheter device. In this manner, the anesthetizing sheath can bedesigned for use with any of a wide variety of existing catheter devicesalready on the market, thereby increasing its versatility.

In a still further embodiment of the invention, rather than using asheath, the outer wall of the catheter device is provided with asecondary lumen, into which the anesthetic agent is injected and fromwhich the anesthetic agent is infused into surrounding subcutaneoustissue.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to more fully understand the manner in which the above-recitedand other advantages and objects of the invention are obtained, a moreparticular description of the invention will be rendered by reference tospecific embodiments thereof which are illustrated in the appendeddrawings. Understanding that these drawings depict only typicalembodiments of the invention and are therefore not to be consideredlimiting of its scope, the invention in its presently understood bestmode for making and using the same will be described with additionalspecificity and detail through the use of the accompanying drawings inwhich:

FIG. 1 is a perspective view illustrating one presently preferredembodiment of the catheter apparatus of the present invention;

FIG. 2 is a cross-sectional view taken along line 2--2 in FIG. 1, andfurther illustrates the catheter apparatus of FIG. 1 disposed within aportion of a patient's body;

FIG. 3 is a cross-sectional view taken along line 3--3 in FIG. 1;

FIG. 4 is an enlarged cross-sectional view taken along line 4--4 of FIG.3, showing a one way slit in a closed position;

FIG. 5 is an enlarged cross-sectional view taken along line 4--4 of FIG.3, showing a one way slit in an open position to permit infusion ofanesthetic agent into surrounding subcutaneous tissue;

FIG. 6 is an exploded perspective view of another presently preferredembodiment of the catheter apparatus of the present invention;

FIG. 7 is a perspective view of the anesthetizing sheath of FIG. 6mounted to a catheter device;

FIG. 8 is a cross-sectional view taken along line 8--8 in FIG. 7;

FIG. 9 is an exploded perspective view of another presently preferredembodiment of the catheter apparatus;

FIG. 10 is a perspective view of the anesthetizing sheath of FIG. 9mounted to a catheter device;

FIG. 11 is a cross-sectional view taken along line 11--11 of FIG. 10;

FIG. 12 is a perspective view of still another embodiment of the presentinvention;

FIG. 13 is an enlarged cross-sectional view taken along lines 13--13 ofFIG. 12;

FIG. 13A is an enlarged cross-sectional view showing an alternativeembodiment of the catheter apparatus of FIG. 12.

FIG. 14 is a perspective view of yet another embodiment of a catheterapparatus constructed in accordance with the inventive concepts of thepresent invention;

FIG. 15 is a cross-sectional view taken along lines 15--15 of FIG. 14,and further illustrates the catheter apparatus of FIG. 14 disposedwithin a portion of a patient's body;

FIG. 16 is an enlarged cross-sectional view taken along lines 16--16 ofFIG. 15;

FIG. 17A is a perspective view of yet another presently preferredembodiment of the anesthetizing sheath mounted to a catheter device;

FIG. 17B is an enlarged perspective view in partial cross-section takenalong lines 17B--17B of FIG. 17A;

FIG. 18A is an enlarged cross-sectional view taken along lines 18A--18Aof FIG. 17B;

FIG. 18B is an enlarged cross-sectional view also taken along lines18A--18A of FIG. 17B, illustrating the manner by which the interiorlumen is compressed so as to close the delivery holes and therebyprevent the entry of bodily fluids into the lumen.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Reference is next made to the drawings, wherein like parts aredesignated with like numerals throughout. Referring first to FIG. 1, onepresently preferred embodiment of the invention is illustrated. FIG. 1represents a perspective view of the catheter apparatus of the presentinvention, designated generally at 10. Catheter apparatus 10 includes acatheter means, as for example a catheter device designated generally at12, for insertion through subcutaneous tissue. As used herein, the termcatheter device is intended to broadly cover the general category ofcannula-type devices referred to as catheters. Thus the term catheterdevice is intended to refer to any hollow, tubular cannula-type devicethat is capable of being inserted into canals, vessels, passageways, orother body cavities so as to permit injection or withdrawal of fluids,or to keep a passage open. Further, the term is intended to includeinsertion devices which are used for controlling, directing and placingmedical devices, such as intubation tubes or dilation catheters, into abody cavity, such as the trachea, a blood vessel, or the heart, andwhich are commonly referred to as intubators, insertion sheaths, and/ordilators.

For purposes of example, the catheter device 12 illustrated in FIG. 1 isan insertion sheath comprised of an indwelling cannula 14 which isadapted for insertion through subcutaneous tissue and into a patient'sbody. As is better shown in FIG. 2, the cannula 14 is inserted into apatient's body (typically via a guide wire while the patient is numbedwith a local anesthetic) so as to have a distal end 17 disposed within abody cavity, such as a blood vessel 16. As is shown, the cannula 14necessarily passes through the patient's skin layer 18 and the area ofsubcutaneous tissue 20 that lies between the skin layer 18 and the bodycavity, such as the blood vessel 16. Thus, once the cannula 14 isproperly positioned, a portion 22 of the cannula 14 remains disposedwithin the area of subcutaneous tissue 20.

Once in place, the insertion sheath cannula 14 is used for controllingand directing the placement of another medical device, as for example adilation catheter 24 for use in a PTCA procedure. The dilation catheter24 is inserted into the hollow cannula 14 via the proximal hub end 26 ofthe catheter device 12, and the tubing 23 and connector 25 attachedthereto. The proximal hub end 26 remains positioned outside of the body.Upon completion of the PTCA (or related) procedure, the dilationcatheter 24 is removed from the cannula 14 through the proximal hub end26. Typically, the distal end portion 17 of the cannula 14 then remainspositioned within the patient, sometimes for as long as twenty-fourhours. At the end of this time period (by which time all numbing effectsof the local anesthesia have worn off) the patient's skin 18 andsubcutaneous tissue 20 are swollen and very sensitive, and retraction ofthe cannula 14 can be extremely painful.

Referring again to FIG. 1, the catheter apparatus 10 of the presentinvention further comprises a sheath means, as for example a hollowcylindrical sleeve generally designated at 28, for placement onto atleast a portion of the cannula 14 at a point intermediate of the distalend 17 and the proximal hub end 26. As is better shown in FIG. 2, thecylindrical sleeve 28 is positioned on the cannula 14 so as to bedisposed on the portion 22 of cannula 14 that is surrounded bysubcutaneous tissue 20 when the cannula 14 is indwelling within thepatient's body.

As is shown in the preferred embodiment of FIGS. 1 and 2, thecylindrical sleeve 28 has a distal end 30 and a proximal end 32. Thecross-sectional view of FIG. 3 illustrates how hollow cylindrical sleeve28 has an inner diameter which is greater than the outer diameter ofcannula 14, and how cylindrical sleeve 28 is positioned on cannula 14 soas to be concentric with the cannula 14. Preferably, distal end 30 ofcylindrical sleeve 28 is tapered where it terminates on the outersurface of cannula 14 so that the cylindrical sleeve 28 can be insertedwith little or no trauma through the outer skin layer 18 andsubcutaneous tissue 20. This tapered distal end 30 is best seen in FIG.2.

The sheath means is further comprised of a means for sealing the sheathmeans in a fluid tight manner around the cannula 14 so as to preventfluids, such as blood from the body, from escaping between the cannula14 and the sheath means. In the embodiment of FIGS. 1 and 2, forexample, this sealing function is accomplished by permanently affixingthe cylindrical sleeve 28 over the outer surface 22 of the cannula 14.Thus, in this embodiment, the distal end 30 of the cylindrical sleeve 28is fused, or otherwise suitably affixed, to the cannula 14. By so doing,fluids are prevented from entering the space or interior lumen 38between the outer surface of the cannula 14 and the cylindrical sleeve28.

The sheath means, as for example cylindrical sleeve 28, is furthercomprised of a means for delivering fluid medicament, such as ananesthetic agent (not shown), to essentially only that portion ofsubcutaneous tissue 20 that surrounds the sheath means. Delivery offluid medicament is accomplished, for example, by way of the interiorlumen 38 running from the distal end 30 to the proximal end 32 of thecylindrical sleeve 28. Delivery of fluid medicament is also aided by ahub means for delivering the fluid medicament to the interior lumen 38,and a plurality of valve means for communicating the fluid medicamentfrom the interior lumen 38 to the subcutaneous tissue surrounding thesheath means.

By way of example, FIG. 2 illustrates cylindrical sleeve 28 as beingcomprised of a single cylindrical wall 36. In this particularembodiment, the interior lumen 38 is formed between the cylindrical wall36 and the outer surface of the cannula 14. Interior lumen 38 is alsoshown in the cross-sectional view of FIG. 3.

By way of further example, FIGS. 1 and 2 illustrate how the hub meanscan be comprised of a hub 40 that is joined in a fluid tight manner tothe proximal end 32 of the cylindrical sleeve 28, and to the proximalhub end 27 of the cannula 14. Hub 40 further comprises, for example, afirst passageway means, such as a first hub lumen 42, for communicatingthe fluid medicament to the interior lumen 38. In addition, hub 40comprises a second passageway means, such as second lumen 44, forproviding fluid communication to the cannula 14 via a cannula accesshole 46. FIG. 1 illustrates how the first and second hub lumens 42, 44are preferably coupled to multi-lumen tube 41. Multi-lumen tube 41 isbranched such that first hub lumen 42 is coupled to an infusion port 43,and second hub lumen is coupled to an I.V. valve assembly 45. In thisway, a medical technician can administer fluid medicament with a syringeto the interior lumen 38 using infusion port 43.

By way of further example, FIG. 1 illustrates how the plurality of valvemeans are preferably comprised of a plurality of one way valve meansspaced along the cylindrical sleeve 28. The one-way valve means not onlyallow the fluid medicament to be communicated from the interior lumen 38to the subcutaneous tissue 20, but also act so as to prevent bodilyfluids from entering the interior lumen 38. The one way valve functionis provided by a plurality of one way slits 48 placed uniformly aboutthe cylindrical sleeve 28. Because the width of the subcutaneous tissue20 will vary from patient to patient, it is possible that the distal end30 of the cylindrical sleeve 28, along with some of the slits 48, couldbe disposed within the blood vessel 16. In this situation, the one wayslits 48 positioned within the portion of subcutaneous tissue 20 willproperly communicate the anesthetic agent to the tissue 20, but any ofthe one way slits 48 that are located within the blood vessel 16 willprevent bodily fluids, such as blood, from entering the interior lumen38.

As is further shown in FIG. 1, each slit 48 is preferably madelongitudinally along the axis of the cylindrical sleeve 28. Slits 48 areuniformly located about the periphery of the cylindrical sleeve 28 so asto insure that the anesthetizing agent is evenly and uniformly deliveredto the surrounding subcutaneous tissue 20. Further, the longitudinallength of each slit 48 changes depending on its location on thecylindrical sleeve 28. Preferably the slits 28 become progressivelyshorter as they near the proximal end 32 of the cylindrical sleeve 28.This variation in slit length is intended to help assure that fluidmedicament is uniformly delivered from the proximal end 32 to the distalend 30 of sleeve 38. This may be especially important if one or moreproximately located slits 48 are located outside of the patient's bodyduring delivery of the fluid medicament.

As is shown in FIGS. 3-5, each one way slit 48 extends completelythrough the cylindrical wall 36 of the cylindrical sleeve 28 so as toprovide fluid communication with interior lumen 38. It is shown best inFIGS. 4 and 5 wherein each slit 48 is defined by opposed, aligned,normally abutting, parallel edges 50. FIG. 4 illustrates how a squareportion 51 of the abutting edges 50 are normally engaged in a sealingrelationship, and wherein the slit 48 is thereby in a closed position.The abutting edges 50 are further formed with rounded internal edgeportions 52 that do not abut, but are spaced apart. In this closedposition (shown in FIG. 4), the slit 48 will prevent any bodily fluidsfrom entering the interior lumen 38.

Wall edges 50 are also capable of flexing outwardly from their closedposition, responsive to a pressure generated within the interior lumen38. In so doing, an orifice 54 is created, through which fluid such asthe anesthetic agent, can flow. This open position is illustrated inFIG. 5. Thus, by applying a predetermined positive pressure to interiorlumen 38, a fluid medicant such as an anesthetic agent is infused intothe area of subcutaneous tissue 20 in which the cylindrical sleeve 28 isdisposed, as shown in FIG. 2.

Slits 48 normally remain closed and wall edges 50 remain in an abuttingposition (FIG. 4). This requires that the cylindrical sleeve 28 havesufficient memory to return the slits 48 to the closed position afterinfusion of anesthetic agent is terminated. The cylindrical sleeve 28may be constructed from a variety of materials with the requiredelasticity. Preferably, the cylindrical sleeve 28 is rigid enough to beeasily inserted into the area of subcutaneous tissue 20 in conjunctionwith the cannula 14. At the same time, the cylindrical sleeve 28 shouldbe flexible enough so as to conform to the movements of the patient, andsuch that the slits 48 exhibit the unidirectional fluid flow propertiesdiscussed above in connection with FIGS. 4 and 5.

In the preferred embodiment, cylindrical sleeve 28 is made from apolyurethane material. Also, Teflon, nylon or polyethylene materials maybe suitable. The sleeve material can have a Shore A durometer in therange from about 80 to about 100 and Shore D durometer in the range of40 to 70, and preferably will be in the range from about Shore D 40 toabout 55.

It will be appreciated that the valve means may be comprised of avariety of equivalent structures. For instance, valve means could becomprised of a plurality of holes formed through the cylindrical wall 36of the cylindrical sleeve 28. Further, this structure could provide aone way fluid flow function if the holes are made sufficiently largewith respect to the width of interior lumen 38. In such an embodiment,the pressures exerted by bodily fluids, such as interstitial bloodpressure, would compress the interior lumen 38 and thereby preventback-flow of bodily fluids back into the interior lumen 38 through theholes. An illustrative example of such an embodiment is described infurther detail below in connection with FIGS. 17A through 18B.

With continued reference to FIGS. 1 and 2, formed on the hub 40 nearproximal end 32 of the cylindrical sleeve 28 is a suture attachment ring47. Once the cylindrical sleeve 28, in conjunction with the insertionsheath cannula 14, has been positioned within the portion ofsubcutaneous tissue 20, the physician can suture, or otherwise attach,the cylindrical sleeve 28 to the patient via the suture attachment ring47. In this manner, the cylindrical sleeve 28 will stay correctlypositioned within the portion of subcutaneous tissue 20 duringsubsequent medical procedures, such as a PTCA. This insures that medicalpersonnel can administer a fluid medicament, such as an anestheticagent, to the subcutaneous tissue 20 without first having to repositionthe cylindrical sleeve 28.

Another embodiment of the catheter apparatus of the present invention isillustrated in FIGS. 6 through 8, and is designated generally at 10b.Catheter apparatus 10b includes a catheter means, as for example acatheter device designated generally at 12 which is essentially the sameas the catheter device discussed in conjunction with FIGS. 1 through 3.That discussion will not be repeated here.

The indwelling catheter apparatus 10b also comprises a a sheath means,as for example a hollow cylindrical sleeve 56, for placement onto atleast a portion of the cannula 14 at a point intermediate of the distalend 17 and the proximal hub end 26 of the cannula 14. However, unlikethe embodiment shown in FIGS. 1 through 3, the sheath means of FIGS. 6through 8 can be selectively attached and detached to the cannula 22, asdiscussed in further detail below.

As is shown in FIGS. 6 and 7, cylindrical sleeve 56 has a distal end 58and a proximal end 60. Hollow cylindrical sleeve 56 further has an innerdiameter which is greater than the outer diameter of cannula 14. Thisrelationship is also shown in the cross-sectional view of FIG. 8. Alsoshown in FIG. 8 is how cylindrical sleeve 56 is positioned, in a tightfitting manner, on cannula 14 so as to be concentric with the cannula14. Preferably, distal end 58 of cylindrical sleeve 56 is tapered withrespect to the outer surface 22 of cannula 14, so that the cylindricalsleeve 56 can be inserted with little or no trauma through the portionof subcutaneous tissue 20 when it is mounted to the cannula 14.

The cylindrical sleeve 56 further comprises a means for delivering fluidmedicament, such as an anesthetic agent, to the subcutaneous tissue 20surrounding the sleeve 56. The fluid medicament delivering meanscomprises, for example, a means for defining an interior lumen runningfrom the distal end 58 to the proximal end 60 of the sleeve 56, a hubmeans through which the fluid medicament is delivered to the interiorlumen, and a plurality of one way valve means for communicating thefluid medicament from the interior lumen to the subcutaneous tissue 20surrounding the sleeve 56 and for preventing fluids from entering theinterior lumen.

By way of example, and referring now to FIG. 8; cylindrical sleeve 56 isillustrated as being comprised of a cylindrical outer wall 62 that isformed over a concentric cylindrical inner wall 64 in a spaced apartrelationship. Thus, in this embodiment, an interior lumen 66 is providedby the space between the outer wall 62 and the inner wall 64.

By way of further example and with continued reference to FIGS. 6 and 7in combination, the hub means is comprised of a first hub 72. In thepreferred embodiment, first hub 72 is joined in a fluid tight manner tothe proximal end 60 of the cylindrical sleeve 56. First hub 72 furthercomprises, for example, a first passageway means, such as a first hublumen (not shown), for communicating the anesthetic agent to theinterior lumen 66. As is shown in FIGS. 6 and 7, the first hub 72 can beattached, for example, to an external tube 74 through which theanesthetic agent can be introduced to the internal lumen 66, as forexample by a syringe (not shown), via an infusion port 76.

FIGS. 6 through 8 further illustrate the preferred embodiment of theplurality of one way valve means spaced along the cylindrical sleeve 56.As is shown, each valve means is comprised of a one way slit 82 that isformed through outer wall 62 of cylindrical sleeve 56. These slits 82are preferably substantially identical to the one way slits 48 describedabove in connection with FIGS. 1 through 3, and that discussion will notbe repeated here.

As is further shown in FIGS. 6 through 8, in this particular embodimentsleeve 56 is further comprised of a means for selectively attaching anddetaching the sleeve 56 from the cannula 14. For example, the means forselectively attaching and detaching is illustrated as being comprised ofa continuous slit 68 that extends longitudinally along the entire lengthof the cylindrical sleeve 56. Slit 68 has a width such that thecylindrical sleeve 56 can be detachably mounted to the cannula 14through the slit 68. The cylindrical sleeve 56 in such a mountedposition is illustrated in FIGS. 7 and 8.

Referring now to FIG. 8, when cylindrical sleeve 56 is mounted tocannula 14, the cylindrical inner wall 64 is in continuous contact withthe outer surface of cannula 14. This tight fitting position ismaintained by the resilient properties that are preferably exhibited bycylindrical sleeve 56. As is further shown, the edges 69 and 69' wherethe outer wall 62 meets inner wall 64 are tapered with respect to theouter surface of the cannula 14. This permits the cylindrical sleeve 56to be inserted with less trauma into the subcutaneous tissue, and itfurther forms a tight seal between the cylindrical sleeve 56 and cannula14 so as to prevent bodily fluids from leaking between sleeve 56 andcannula 14. The sheath means of this embodiment is also comprised of ameans for sealing the sheath means in a fluid tight manner around thecannula 14 so as to prevent fluids, such as blood from the body, fromescaping between the cannula 14 and the sleeve 56. For example, as isshown in both FIGS. 6 and 7, this sealing is accomplished by placing anO-ring 70 between the cylindrical sleeve 56 and the outer surface of thecannula 14. Thus, when the cylindrical sleeve 56 is mounted to thecannula 14, O-ring 70 forms a fluid-tight seal, and thereby prevents anybodily fluids from leaking between sleeve 56 and cannula 14. Cylindricalsleeve 56 also has formed thereon a suture attachment ring 47, similarto the ring 47 discussed above in connection with FIGS. 1 through 3.

In the embodiment of FIGS. 6 and 7, the indwelling catheter apparatusfurther includes a second hub means, as for example hub 78, forproviding fluid communication to the cannula 14. Hub 78 is joined in afluid tight manner to the proximal end of cannula 14. As is also shown,hub 78 can be connected to external tube 80, through which fluids may beinfused to cannula 14. A dilation catheter may be introduced intocannula 14 through tubing 23 and connector 25.

Yet another embodiment of the indwelling catheter apparatus of presentinvention is illustrated in FIGS. 9 through 11, and is designatedgenerally at 10c. Indwelling catheter apparatus 10c also includes acatheter means, as for example a catheter device, which is essentiallythe same as the catheter device discussed in conjunction with FIGS. 1through 3.

The indwelling catheter apparatus 10c also comprises a sheath means, asfor example a hollow cylindrical sleeve 86, for placement onto at leasta portion of the cannula 14 at a point intermediate of the distal end 17and the proximal hub end 26 of the cannula 14. As with the embodimentshown in FIGS. 6 through 8, the sheath means of FIGS. 9 through 11 canbe selectively attached and detached to the cannula 14, as will bediscussed in further detail below.

As is shown in FIGS. 9 and 10, cylindrical sleeve 86 has a distal 88 anda proximal end 90. Hollow cylindrical sleeve 86 further has an innerdiameter which is greater than the outer diameter of cannula 14. Thisrelationship is also shown in the cross-sectional view of FIG. 11. Alsoshown in FIG. 11 is cylindrical sleeve 86 positioned in a tight fittingmanner on cannula 14 so as to be concentric with the cannula 14.Preferably, distal end 88 of cylindrical sleeve 86 is tapered withrespect to the outer surface of cannula 14, so that the cylindricalsleeve 86 can be inserted with little or no trauma through the portionof subcutaneous tissue 20 when it is mounted to the cannula 14.

The cylindrical sleeve 86 further comprises a means for delivering fluidmedicament, such as an anesthetic agent (not shown), to the subcutaneoustissue 20 surrounding the sleeve 86. The fluid medicament deliveringmeans comprises, for example, a means for defining an interior lumenrunning from the distal end 88 to the proximal end 90 of the sleeve 86,a hub means through which the fluid medicament is delivered to theinterior lumen, and a plurality of one way valve means for communicatingthe fluid medicament from the interior lumen to the subcutaneous tissuesurrounding the sheath means and for preventing fluids from entering theinterior lumen.

By way of example, and referring now to FIG. 11, cylindrical sleeve 86is illustrated as being comprised of a cylindrical outer wall 92 that isformed over a concentric cylindrical inner wall 94 in a spaced apartrelationship. Thus, in this embodiment, interior lumen 96 is provided bythe space which is formed between the outer wall 92 and the inner wall94.

By way of further example and with reference now to FIGS. 9 and 10 incombination, the hub means is comprised of a first hub 98 joined in afluid tight manner to the proximal end 90 of the cylindrical sleeve 86.First hub 98 further comprises, for example, a first passageway means,such as a first hub lumen (not shown), for communicating the fluidmedicament to the interior lumen 96. As is shown in FIGS. 9 and 10, thefirst hub 98 can be attached, for example, to an external tube 100through which the fluid medicament can be introduced to the internallumen 96, as for example by syringe (not shown), via an infusion port102.

FIGS. 9 through 11 further illustrate the preferred embodiment of theplurality of one way valve means spaced along the cylindrical sleeve 86.As is shown, each valve means is comprised of a one way slit 104 that isformed through outer wall 92 of cylindrical sleeve 86. These slits 104are preferably substantially identical to the one way slits 48 describedabove in connection with FIGS. 1 through 3.

As is further shown in FIGS. 9 and 10, in this particular embodiment thesleeve 86 is further comprised of a means for selectively attaching anddetaching the cylindrical sleeve 86 from the cannula 14. For example,selective attachment and detachment is illustrated as being accomplishedby longitudinally sliding the hollow cylindrical sleeve 86 onto cannula14. The cylindrical sleeve 86 in such a mounted position is illustratedin FIGS. 10 and 11.

When cylindrical sleeve 86 is thus mounted to cannula 14, thecylindrical inner wall 94 is in a continuous and tight fitting contactwith the outer surface of cannula 14. The inner diameter of thecylindrical sleeve 86 with respect to the outer diameter of cannula 14is such that the sleeve 86 remains positioned on the cannula 14 in aslidable, yet tight fitting manner.

The sleeve 86 of this embodiment is also comprised of a means forsealing the sleeve 86 in a fluid tight manner around the cannula 14 soas to prevent fluids, such as blood from the body, from escaping betweenthe cannula 14 and the sleeve 86. For example, as is shown in FIG. 9,this sealing means is accomplished by placing an O-ring 106 between theinner surface of the cylindrical sleeve 86 and the outer surface of thecannula 14. Thus, when the cylindrical sleeve 86 is mounted to thecannula 14, O-ring 106 forms a fluid-tight seal, and thereby preventsany bodily fluids from leaking between sleeve 86 and cannula 14.Cylindrical sleeve 86 also has formed thereon a suture attachment ring47, similar to the ring 47 discussed above in connection with FIGS. 1through 3.

In the embodiment of FIGS. 9 and 10, the indwelling catheter apparatusfurther includes a second hub means, as for example hub 108, forproviding fluid communication to the cannula 14. Hub 108 is joined in afluid tight manner to proximal hub end 26 of cannula 14. As is alsoshown, hub 108 can be connected to external tube 110, through whichfluids may be infused to cannula 14.

As discussed, the cylindrical sleeves 56, 86 of the two embodiments ofFIGS. 6 through 8 and 9 through 11 are not permanently mounted to anyparticular catheter device 12, but can be selectively attached anddetached to preexisting catheter devices. Consequently, the versatilityof a single cylindrical sleeve is greatly enhanced because it can beused with any one of a variety of catheter devices that are already onhand. Thus, when using a preexisting catheter device, medical personnelcan retrofit the device with a cylindrical sleeve discussed inconnection with FIGS. 6 through 11, and provide the patient with thepain relief that would not otherwise be available with that catheterdevice. Importantly, this retrofit capability provides the advantages ofpain relief, yet simultaneously protects any investment already made ina stock of preexisting catheter devices.

It will be appreciated that although the only difference between theembodiment of FIGS. 6 through 8 and the embodiment of FIGS. 9 through 11lies in how the cylindrical sleeve 56 or 86 is attached and detached tothe cannula 14, the difference in how the two embodiments are used ismore significant. In use, cylindrical sleeve 56 (FIGS. 6-8) attaches anddetaches to the cannula 14 by way of the longitudinal slit 68 formedalong the length of the sleeve 56. Thus, the sleeve 56 can be attachedto a cannula 14 even if the cannula 14 has already been inserted in thepatient. For instance, a doctor may insert a catheter device, such as aninsertion sheath, perform the underlying procedure and, when completed,snap on the cylindrical sleeve 56 to the proximate portion of thecannula 14. Since the patient is still locally anesthetized from thepreviously performed medical procedure, the sleeve 56 can then beinserted into the portion of subcutaneous tissue 20 with the cannula 14.When the cannula 14 is later retracted (and the previously administeredlocal anesthetic has worn off) the doctor can readminister a localanesthetic to the subcutaneous tissue 20 through sleeve 56 and thenpainlessly retract the cannula 14. In this way, the doctor or medicaltechnician is not distracted by the extra equipment, tubes, infusionports, etc. associated with cylindrical sleeve 56 while the underlyingmedical procedure, such as a PTCA, is being done.

In contrast, cylindrical sleeve 86 (FIGS. 9-11) attaches and detaches tothe cannula 14 by sliding the sleeve 86 onto the cannula 14.Consequently, the sleeve 86 of this embodiment cannot be placed on acannula 14 that has already been inserted in a patient, and mustnecessarily be positioned on the cannula 14 before the underlyingmedical procedure is done and thus before cannula 14 is initiallyinserted into the patient. However, under certain circumstances thisapproach may be entirely acceptable and/or desirable.

FIGS. 12 and 13 illustrate yet another embodiment of the indwellingcatheter apparatus of the present invention, designated generally at10d. As in the embodiments previously discussed, catheter apparatus 10dincludes a catheter means, as for example a catheter device, which isessentially the same as the catheter device of the previous embodiments.

The indwelling catheter apparatus 10d also has a sheath means forplacement onto the cannula 14. By way of example and referring now toFIG. 12, sheath means is comprised of a helical sheath, designatedgenerally at 120. As is shown, helical sheath 120 is comprised of asingle band 122 that is wound in a helical fashion so as to conform tothe cylindrical outer periphery of the cannula 14. The helical sheath120 has a proximate end 124 and a distal end 126, and is preferablypositioned on the cannula 14 so that it can be disposed within the areaof subcutaneous tissue 20 in conjunction with the cannula 14 (in thesame manner illustrated in FIG. 2).

Referring now to FIG. 13, the band 122 that forms helical sheath 120 hasa substantially flat cross-section when it is placed on the cannula 14.Further, when positioned on the cannula 14, band 122 has successiveleading edges 128 and trailing edges 130 that are tapered with respectto the outer surface of the cannula 14. Advantageously, when the helicalsheath 120 is mounted to the cannula 14, this flat cross-section and thetapered leading and trailing edges 128, 130 of band 122 act so as toease the insertion and retraction of the helical sheath 120 through thepatient's skin and subcutaneous tissue 20 when it is mounted to thecannula 14. Similarly, this configuration minimizes trauma to the skinor subcutaneous tissue 20 when the helical sheath 120 is inserted andretracted.

Alternatively, FIG. 13A illustrates another cross-sectional shape thatmay be formed by band 122. In this embodiment, band 122 is placed oncannula 14 in a tight helical fashion such that the leading edges 128abut against the adjacent trailing edges 130. Further, each leading edge128 slopes upwardly towards the trailing edge 130 to form an overalltapered shape. In this way, the helical sheath 120 has an overalltapered shape so as to permit easier insertion through the patient'sskin and subcutaneous tissue 20.

Helical sheath 120 is further comprised of a fluid medicament deliverymeans for delivering a fluid medicament, such as an anesthetic agent, tothe subcutaneous tissue 20 in which the helical sheath 120 is disposed.By way of example, FIGS. 12 and 13 illustrate how the fluid medicamentdelivery means is preferably comprised of a means for defining aninterior lumen running from the distal end 126 to the proximal end 124of helical sheath 120. As is shown, lumen means is comprised of aninterior lumen 132 that is defined by a hollow portion formed withinband 122. The hollow portion that defines interior lumen 132 extendsalong the entire length of helical sheath 120.

Helical sheath 120 is also preferably comprised of a hub means throughwhich the anesthetic agent is delivered to the interior lumen 132. AsFIG. 12 illustrates, hub means is comprised, for example, of a tube 134which is coupled in a fluid tight manner to the proximal end 124 of thehelical sheath 120. Tube 134 has a single lumen 136 that is in fluidcommunication with the interior lumen 132. Anesthetic agent can bedelivered to interior lumen 132 through a fluid injection port 138connected to the opposite end of tube 134. FIG. 12 further illustrateshow hub means also comprises, for example, a hub 135 that is connectedin a fluid tight manner to the proximal hub end 26 of cannula 14. Hub135 is essentially identical to hub 108 discussed in connection with theembodiment of FIG. 10, and thus that discussion will not be repeated.

With continued reference to FIG. 12, helical sheath 120 also comprises aplurality of one way valve means for communicating the anesthetic agentfrom the interior lumen 132 to the subcutaneous tissue 20 surroundingthe sheath 120, and at the same time, for preventing bodily fluids, suchas blood, from entering the interior lumen 132. For example, FIGS. 12and 13 illustrate how the valve means are each comprised of a one wayslit 140 that is formed through the band 122 to interior lumen 132. Oneway slits 140 are placed uniformly along helical sheath 120, and areessentially identical to the one way slits discussed above in connectionwith the embodiments of FIGS. 1 through 11.

As discussed generally, helical sheath 120 may further comprise a meansfor selectively attaching and detaching the helical sheath 120 to thecannula 22. This function is provided by wrapping the helical sheath 120onto the longitudinal length of cannula 14 so that the helical sheath120 is concentrically positioned on the cannula, as is illustrated inFIG. 12. It will be appreciated that, like the embodiment of FIGS. 6through 8, helical sheath 120 can be detachably mounted to a cannula 14even after the cannula 14 has already been inserted into the patient.Preferably, the helical sheath 120 exhibits sufficient resilientproperties such that once it is positioned on the cannula 14, it remainspositioned in a tight fitting manner. Alternatively, once helical sheath120 has been detachably mounted to the cannula 14, the medicaltechnician may further adhere the sheath 120 to the cannula 14 byapplying a small amount of liquid adhesive. Thus, helical sheath 120 canbe selectively used on a variety of preexisting catheter devices.Alternatively, cannula 14 can be manufactured with a helical sheath 120premounted in the manner illustrated in FIG. 12. In this instance,helical sheath 120 would be affixed permanently to the catheter device12 by fusing, or similarly adhering it to the cannula 14.

Referring now to FIGS. 14 through 16, yet another preferred embodimentof indwelling catheter apparatus, designated generally at 10e, is shown.Indwelling catheter apparatus 10e includes a catheter means, as forexample a catheter device 12, that has a cannula 14 for insertionthrough subcutaneous tissue 20 into a patient's body (shown in FIG. 15).The catheter device 12 is essentially identical to the catheter devicedescribed in conjunction with the previous embodiments, having anindwelling distal end 17 and a proximal hub end 26. FIG. 15 furtherillustrates how cannula 14 is a cylindrical tube having a cylindricalouter wall 150, through which a primary lumen 152 runs.

Indwelling catheter apparatus 10e also comprises a means for deliveringa fluid medicament, such as an anesthetic agent, to essentially only thearea of subcutaneous tissue 20 through which the cannula 14 is inserted.For example, in the embodiment of FIGS. 14 through 16, the means fordelivering a anesthetic agent is comprised of a secondary lumen that isformed in the outer wall 150 of the cannula 14. FIGS. 15 and 16illustrate how the secondary lumen is preferably comprised of aplurality of longitudinal bores 154 formed within the outer wall 150. Asis further shown, the plurality of bores 154 are uniformly spaced aboutthe circumference of the cannula 14, and each bore 154 is substantiallyparallel to the primary lumen 152 running through the cannula 14.Further, the plurality of bores 154 that form the secondary lumen arepreferably formed in the cannula 14 outer wall 150 so that they aresubstantially disposed within the area of subcutaneous tissue 20 oncethe cannula 14 has been inserted within the patient's body. In this way,secondary lumen, as defined by the plurality of bores 154, candistribute the anesthetic agent to the subcutaneous tissue 20 evenly anduniformly.

The anesthetic agent is communicated to the surrounding subcutaneoustissue 20 from the secondary lumen 154 through a plurality of one wayvalve means, which also act to prevent bodily fluids from entering thesecondary lumen 154. As FIG. 14 illustrates, the one way valve means areeach comprised of a single one way slit 156 that is formed through theouter wall 150 to each of the plurality of longitudinal bores 154. Thisis illustrated in further detail in the exploded cross-section view ofFIG. 16, where one way slits 156 are illustrated. Each of the one wayslits 156 are substantially identical to the one way slits discussedabove in connection with the other preferred embodiments.

To deliver the anesthetic agent to the secondary lumen 154, the fluidmedicament delivery means is further comprised of a hub means. This hubmeans is illustrated as being comprised of a single hub 158, that isjoined in a fluid tight manner to the proximal hub end portion 27 of thecannula 14. FIGS. 14 and 15 illustrate how hub 158 is formed with afirst hub lumen 42 and a second hub lumen 44. First hub lumen 42 iscoupled to each of the longitudinal bores 154 that form the secondarylumen so as to provide a passageway for delivering anesthetic agent.Similarly, second hub lumen 44 is coupled to the primary lumen 152 via acannula access hole 46, thereby providing a separate fluid passagewayfor that lumen. As FIG. 14 illustrates, the first and second hub lumens42, 44 are connected to a multi-lumen tube 41, through which the firsthub lumen 42 is connected to an infusion port 43, and second hub lumen44 is connected to an I.V. valve assembly 45. Thus, anesthetic agent canbe delivered to the bores 154 that form the secondary lumen with asyringe by using infusion port 43.

Referring next to FIGS. 17A-B and 18A-B, yet another embodiment of thepresent invention is shown. FIG. 17A illustrates an indwelling catheterapparatus 10f having a sheath means that is comprised of a hollowelongate band, wrapped in a helical fashion about cannula 14. Thishelical sheath, designated generally at 120, is substantially identicalto the helical sheath 120 shown in FIG. 12. The identical portions ofthat device are designated with like numerals in FIG. 17A, and theirdescription will not be repeated. However the embodiment of FIG. 17Adiffers from that of FIG. 12 in the manner by which the valve means isconstructed.

As is shown by way of example in FIG. 17A, in this particular embodimentthe valve means is comprised of a plurality of delivery holes,designated at 180, which are substantially circular in shape andarranged uniformly along the length of the elongate band 122 that formsthe helical sheath 120. FIG. 17B illustrates in further detail how eachcircular hole 180 is formed completely through the outer surface 182 ofthe band 122 so as to provide a fluid communication path with theinterior lumen 132 formed within the band 122. Each hole 180 acts as afluid path for delivering the anesthetic agent, or similar fluidmedicament, to the subcutaneous tissue that is coextensive with thehelical sheath 120 when it is inserted into the patient.

In the preferred embodiment, the helical sheath 120 is constructed of aslightly flexible material, such as a polyurethane, Teflon,polyethylene, or similarly flexible and medically suitable material.When fluid medicament is to be delivered to the subcutaneous tissue 20of a patient, a positive fluid pressure is generated within the interiorlumen 132, as for example by way of a syringe (not shown) that isconnected to the injection port 138. In this pressurized state,illustrated in cross-section in FIG. 18A, the interior lumen 132 expandsand thereby opens each of the holes 180. In this "open state," fluidmedicament is delivered from the interior lumen 132, through the opendelivery holes 180, and to the subcutaneous tissue 20.

The delivery holes 180 also prevent bodily fluids and/or fluidmedicament from re-entering the interior lumen 132. The flexibility ofthe material used to form the helical sheath 120 and the size of theholes 180 together act to perform this function. When the sheath 120 ispositioned within the subcutaneous tissue 20 and medicament is not beingdelivered, there is no fluid pressure present within the lumen 132.Instead, the pressure exerted on the exterior surface 182 of the sheath120, such as that which would be caused by the surrounding subcutaneoustissue 20 and the interstitial blood pressure, compresses the interiorlumen 132 and causes the lumen walls 184, 186 (shown in FIG. 17B) tocollapse against one another. This condition is best seen in thecross-sectional illustration of FIG. 18B. As is shown in this compressedstate, the delivery holes 180 no longer provide a fluid communicationpath to the interior lumen 132, and external bodily fluids are therebyprevented from entering the lumen 132.

In the preferred embodiment, each of the delivery holes 180 aregenerally circular in shape, and are all of the same approximatediameter. However, it will be appreciated that the holes 180 can havevarious different shapes and yet provide the function described above.Also, if desired the hole 180 sizes can be varied, thereby controllingthe amount of medicament that is delivered to the subcutaneous tissue20.

Also, although this embodiment discloses the use of delivery holes 180on a helical sheath 120, it will be appreciated that the holes 180 couldalso be used in conjunction with the other sheath embodiments describedabove.

The present invention may be embodied in other specific forms withoutdeparting from its spirit or essential characteristics. The describedembodiments are to be considered in all respects only as illustrativeand not restrictive. The scope of the invention is, therefore, indicatedby the appended claims rather than by the foregoing description. Allchanges which come within the meaning and range of equivalency of theclaims are to be embraced within their scope.

What is claimed and desired to be secured by United States Patent is: 1.An indwelling catheter apparatus comprising:catheter means for insertionthrough subcutaneous tissue, said catheter means comprising anindwelling cannula adapted for insertion through subcutaneous tissueinto a patient's body, and having an indwelling distal end and aproximal hub end adapted for securement outside of the body; and sheathmeans for placement over and around at least a portion of said cannulaand into but essentially not beyond the subcutaneous tissue after thecannula is inserted, and for delivering fluid medicament to essentiallyonly the subcutaneous tissue surrounding said cannula, said sheath meansincluding a plurality of delivery holes, each of said delivery holesproviding a fluid communication path between the sheath means and thesurrounding subcutaneous tissue for said fluid medicament.
 2. Anindwelling catheter apparatus as defined in claim 1 wherein said cannulais comprised of a cylindrical tube having a cylindrical outer wall, andwherein a primary lumen runs through said tube, and wherein said sheathmeans comprises at least one interior lumen, and wherein the pluralityof delivery holes are formed on the sheath means so as to each be influid communication with said at least one interior lumen.
 3. Anindwelling catheter apparatus as defined in claim 2 wherein said sheathmeans further comprises hub means for delivering the fluid medicament tosaid at least one interior lumen.
 4. An indwelling catheter apparatus asdefined in claim 3 wherein said hub means comprises an infusion port,the infusion port being in fluid communication with the at least oneinterior lumen.
 5. An indwelling catheter apparatus as defined in claim3 wherein said hub means comprises first passageway means forcommunicating the fluid medicament to said interior lumen, and secondpassageway means for providing fluid communication to said primarylumen.
 6. An indwelling catheter apparatus as defined in claim 1 whereinthe sheath means comprises means for sealing the sheath means in a fluidtight manner around the cannula so as to prevent fluids from the bodyfrom escaping between the cannula and the sheath means.
 7. An indwellingcatheter apparatus as defined in claim 1 wherein the sheath means iscomprised of a cylindrical member having at least one interior lumenformed therein, and wherein the plurality of delivery holes are formedon the cylindrical member so as to be in fluid communication with the atleast one interior lumen.
 8. An indwelling catheter apparatus as definedin claim 1 wherein the sheath means is comprised of a cylindrical memberhaving at least one interior lumen formed therein, and wherein theplurality of delivery holes are formed on the cylindrical member so asto be in fluid communication with the at least one interior lumen, thecylindrical member further having a means for selectively attaching anddetaching the cylindrical member from said cannula.
 9. An indwellingcatheter apparatus as defined in claim 1 wherein the sheath means iscomprised of an elongate band wrapped in a helical fashion around saidcannula.
 10. An indwelling catheter apparatus as defined in claim 9wherein at least one interior lumen is formed within said elongate bandand wherein the plurality of delivery holes are formed on the elongateband so as to be in fluid communication with said interior lumen.
 11. Anindwelling catheter apparatus comprising:catheter means for insertionthrough subcutaneous tissue, said catheter means comprising anindwelling cannula adapted for insertion through subcutaneous tissueinto a patient's body, and having an indwelling distal end and aproximal hub end adapted for securement outside of the body; and sheathmeans for placement over and around the outer circumference of at leasta portion of said cannula intermediate said distal and proximal endsafter the cannula is inserted, such that said sheath means is capable ofbeing inserted into but essentially not beyond the subcutaneous tissue,said sheath means having distal and proximal ends and comprising meansfor defining an interior lumen running from the distal to the proximalend of the sheath means, and said sheath means further comprising:aplurality of delivery holes, spaced along said sheath means from thedistal to the proximal end thereof, each of the delivery holes providinga fluid communication path between said interior lumen and thesurrounding subcutaneous tissue; and hub means for delivering fluidmedicament to said interior lumen.
 12. An indwelling catheter apparatusas defined in claim 11 wherein said sheath means comprises a cylindricalsleeve having the interior lumen formed therein, and wherein thecylindrical sleeve is placed on the cannula so as to be concentric withsaid cannula.
 13. An indwelling catheter apparatus as defined in claim11 wherein said sheath means comprises an elongate band, the elongateband being wrapped over and around the outer circumference of thecannula in a helical manner, and wherein the interior lumen is formedwithin the elongate band.
 14. An indwelling catheter apparatus asdefined in claim 12 wherein the cylindrical sleeve is affixed to saidcannula.
 15. An indwelling catheter apparatus as defined in claim 13wherein the elongate band is affixed to said cannula.
 16. An indwellingcatheter apparatus as defined in claim 13 wherein the elongate band isjoined in a fluid tight manner to said hub means at the proximal end ofsaid elongate band, and wherein said hub means comprises firstpassageway means for communicating the fluid medicament to said interiorlumen.
 17. An indwelling catheter apparatus as defined in claim 16wherein the hub means comprises an infusion port, the infusion portbeing in fluid communication with the interior lumen.
 18. An indwellingcatheter apparatus as defined in claim 11 wherein said sheath meansfurther comprises means for selectively attaching and detaching thesheath means over and around the outer circumference of the cannula. 19.A catheter apparatus for insertion through subcutaneous tissue into apatient's body so as to be indwelling within the body, and for deliveryof anesthetic agents to subcutaneous tissue surrounding the indwellingcatheter apparatus prior to removal thereof to minimize pain to thepatient upon removal of the indwelling catheter apparatus,comprising:catheter means for insertion through subcutaneous tissue,said catheter means comprising an indwelling cannula adapted forinsertion through subcutaneous tissue into a patient's body, and havingan indwelling distal end and a proximal hub end adapted for securementoutside of the body; an elongate band having distal and proximal ends,the band being wrapped over and around the outer circumference of thecannula in a helical manner so as to be capable of being inserted intobut essentially not beyond the subcutaneous tissue, the elongate bandfurther comprising:an interior lumen formed within the band andextending from the distal to the proximal end of the band; a pluralityof delivery holes spaced uniformly along the length of the elongateband, each of said delivery holes being substantially circular in shape,and formed through the outer surface of the band so as to provide afluid communication path between the interior lumen and the surroundingsubcutaneous tissue; and hub means for delivering the fluid medicamentto the interior lumen.
 20. An improved catheter apparatus having acannula adapted for insertion through subcutaneous tissue into apatient's body so as to be indwelling within the body, and wherein theimprovement comprises:sheath means for placement onto at least a portionof the indwelling cannula and for delivery of anesthetic agents tosubcutaneous tissue surrounding the indwelling cannula and sheath meansprior to removal of the cannula so as to minimize pain to the patientupon removal of the indwelling cannula, said sheath means having distaland proximal ends and comprising means defining an interior lumenrunning from the distal to the proximal end of the sheath means, andsaid sheath means further comprising means for selective attachment anddetachment from said cannula, and a plurality of delivery holes, spaceduniformly along said sheath means from the distal to the proximal endthereof, each of which form a fluid communication path between saidlumen and the subcutaneous tissue surrounding said sheath means fordelivery of the anesthetizing agents; and hub means, joined to theproximal end of the sheath means, for delivering the anesthetizingagents to the interior lumen of said sheath means.